1. Field of the Invention
This invention relates to an article for providing a protective covering to a substrate and to methods of applying and securing such an article to a substrate.
2. Introduction to the Invention
Structures such as, for example, supports, e.g. for oil rigs or piers, and pipes commonly require protection from mechanical abuse and corrosion. It is well known to provide such protection by providing a protective covering, e.g. a sleeve or tape on the structure. In order to provide an effective and reliable protective covering it is often necessary to apply the covering in the factory prior to installation of the structure. However, with time, such coverings fail to maintain their protection due to mechanical abuse, e.g. soil stresses or wave battering, poor resistance to heat or cold and/or moisture, and poor initial application of the covering. When failure of the covering occurs it is normally necessary to remove the original covering and apply a new covering to the structure. In addition, when pipes are connected, e.g. welded, together it is normally necessary to apply a protective covering to the exposed pipe joint.
It is often difficult to apply an effective and long-lasting protective covering to a structure that is in its operational location. This may be partly due to the difficulty of ensuring that the covering is applied to the structure without defects and partly due to the fact that conditions in the field often prevent the use of equipment or techniques that may be used in the factory.
One successful method of applying a protective covering to a structure, e.g. a pipeline, in the field is disclosed in European Patent Application No. 0181233, the entire disclosure of which is incorporated herein by reference. This method comprises coating the pipeline with a liquid curable polymeric primer, e.g. an epoxy resin, and then applying one or more polymeric layers, e.g. a tape or sleeve, the innermost layer of which is capable of interacting with the curable polymeric primer in order to form a secure attachment to the structure. The method has the advantage that it does not require the high temperatures and complex equipment needed in some previous coating methods, notably the so-called `fusion-bonded epoxy` methods, for example as disclosed in U.S. Pat. Nos. 4,213,486, 4,510,007 and 3,502,492.